scholarly journals A Review of the Multi-Physical Characteristics of Plant Aggregates and Their Effects on the Properties of Plant-Based Concrete

2021 ◽  
Vol 03 (02) ◽  
pp. 1-1
Author(s):  
Herinjaka Haga Ratsimbazafy ◽  
◽  
Aurélie Laborel-Préneron ◽  
Camille Magniont ◽  
Philippe Evon ◽  
...  

The use of plant aggregates obtained from agricultural co-products mixed with mineral binders to form eco-friendly insulating building materials has been initiated for a few years to bring environmentally friendly solutions to the construction sector. Several studies on different agro-resources have already been carried out, providing various information about the properties of plant aggregates and plant-based concrete. However, the characteristics of the agricultural co-product, which allow it to qualify as a plant aggregate for plant-based concrete, are not yet very clear despite the multitude of data, especially on hemp concrete. Therefore, it is important to gather numerous but very disparate pieces of information available in the literature concerning the properties of plant aggregates and their correlations with composites. This review is based on the results of 120 articles and aims to identify the characterization methods and the multi-physical properties of plant aggregates affecting those of plant-based concrete and to propose additional factors that could influence the properties of the composites. A total of 18 plant aggregates of different origins used for plant-based concrete have been listed in the literature. In France, hemp shiv is the most studied one, but its quantity is quite low unlike cereal or oilseed straws and wood transformation residues. With the existence of several characterization methods, properties like microstructure, particle size distribution, bulk density, water absorption capacity, and chemical composition of aggregates are easily and frequently determined. In contrast, data on the apparent density of particles, the skeleton density, and the hygro-thermal properties of aggregates are rare. The particle size, density, and porosity have been identified as important parameters influencing the properties of the composites. Other parameters related to the behavior of the aggregates under wet compaction and compression of their stacking can also predict the physical and mechanical properties of the obtained plant-based concrete. Dosages of the constituents should be preferred as formulation parameters for future studies assessing the impact of the aggregate properties on the composites.

2007 ◽  
Vol 539-543 ◽  
pp. 1863-1867 ◽  
Author(s):  
X.F. Tao ◽  
Li Ping Zhang ◽  
Y.Y. Zhao

This paper investigated the mechanical response of porous copper manufactured by LCS under three-point bending and Charpy impact conditions. The effects of the compaction pressure and K2CO3 particle size used in producing the porous copper samples and the relative density of the samples were studied. The apparent modulus, flexural strength and energy absorption capacity in three-point bending tests increased exponentially with increasing relative density. The impact strength was not markedly sensitive to relative density and had values within 7 – 9 kJ/m2 for the relative densities in the range 0.17 – 0.31. The amount of energy absorbed by a porous copper sample in the impact test was much higher than that absorbed in the three-point bending test, impling that loading strain rate had a significant effect on the deformation mechanisms. Increasing compaction pressure and increasing K2CO3 particle size resulted in significant increases in the flexural strength and the bending energy absorption capacity, both owing to the reduced sintering defects.


Author(s):  
Herinjaka Haga Ratsimbazafy ◽  
Aurélie Laborel-Préneron ◽  
Camille Magniont ◽  
Philippe Evon

The valorization of available agricultural by-products is important for the development of bio-aggregate based concretes as eco-friendly solutions for building materials. However, their diversity requires to assess their potential of use in vegetal concretes. This study aims to propose simple and relevant multi-physical characterization methods for plant aggregates. Basic and complementary characterizations were carried out on hemp shiv as a reference plant aggregate, and nine by-products available in the South-West part of France, i.e., oleaginous flax shiv, sunflower pith and bark, coriander straw, wheat straw, wheat chaff, corn shuck, miscanthus stem and vine shoot. The basic characterizations performed were those recommended by the TC-RILEM 236 BBM, i.e., particle size distribution, bulk density, water absorption and thermal conductivity. Complementary characterizations have also been proposed, taking into account the possible environment of the binder and the vegetal concrete manufacturing method. The additional tests developed or adapted from previous research assess the following properties: the content of water-soluble compounds at pH 7 and 12, the dry density of plant aggregates compacted in wet state, the real water absorption after compaction and the compression behavior of these compacted aggregates. This complete characterization highlights the distinct behavior of the different agroresources and allows to correlate these characteristics to the use properties of hardened composites.


2020 ◽  
Author(s):  
Yulia Orlovska ◽  
◽  
Daria Havrylenko ◽  

The main international trends in the world market of construction materials and services have been analyzed. The dynamics of world GDP and exports of construction services for the period 2000-2019 has been studied and a conclusion is made on the impact of economic crises on their growth rates. It has been determined that the dynamics of world exports of construction services is characterized by high instability with peaks of growth and decline, and is more sensitive than GDP growth. It has been noted that overcoming the crisis in the export sector of construction services takes more time and occurs with an approximate two-year time lag compared to GDP dynamics. The share of the construction industry in the world GDP by the degree of development has been analyzed. The reasons for the decline in the share of the construction industry in countries with economies in transition have been substantiated. It has been noted that in the developed countries the share of the construction sector is accounted for by real estate management activities related to maintenance, rent, purchase and sale and other transactions with land and real estate. The forecast values of growth of the market of building materials and services till 2030 have been given. The essence of the term «wide construction» has been revealed and the structure of this sector in different countries of the world is shown. The main exporters in the world construction market have been given and the structural distribution of the largest construction companies in the world ranking by country of origin has been analyzed. The dynamics of income level in the construction industry market for the period 2011-2018 has been studied. It has been noted that an important area of the construction sector is the market of roofing and facade materials and the world's largest companies for the production of this type of construction materials have been revealed. Conclusions on the essence of global transformations of the market of building materials and services have been made, and also it has been defined that they are caused by transnationalization of corporate structure of the market, influence of scientific and technical progress and information and communication technologies on world centers as well as the emergence of the concept of «sustainable construction» in the course of humanity for sustainable development.


Author(s):  
Youssef El Moussi ◽  
Laurent Clerc ◽  
Jean-Charles Benezet

The use of bio-based concretes performed with lignocellulosic aggregates constitute an interesting solution for reducing the energy consumption, greenhouse gas emissions and CO2 generated by the building sector. Indeed, bio-based materials could be used as an alternative of traditional materials such as expended polystyrene and mineral resources (e.g. glass and rock wools) for insulation. Furthermore, these bio-based concretes are known for their interesting insulation properties, indeed they allow to enhance thermal properties of buildings and enables moisture management which lead to design efficient building materials. For this purpose, bio-based concrete using rice straw as aggregate are studied in this present work. The impact of the characteristics of rice straw particle (particle size distribution, bulk density, and water absorption capacity, etc.) on both the mechanical and thermal properties of the bio-based concrete are investigated. Five formulations of rice straw concrete are examined, compared and then classified in terms of insulation properties and mechanical properties. The assessments are based on the measurement of density and thermal conductivity. The variation of compressive strength in function of the characteristics (mean particle length) of rice straw particle are assessed and discussed. The investigation covers also the porosity and density. Tests are also carried out on agricultural by-products with a view to highlight their chemical, physical and structural proprieties. The results show that the use of large particles with low water absorption capacity induce lighter concretes with the density between 339 and 505 kg/m3 and lead to a high compressive strength with a high mechanical deformability. Furthermore, it appears that an increase in the average length of rice straw particle lead to decrease of thermal conductivity of bio-based concretes. It varies from 0.062 to 0.085 W/(m.K).


2021 ◽  
Author(s):  
Xiaolong Wang ◽  
Jianling Gu ◽  
Song Xu ◽  
Shengdong Gu

The physical and mechanical properties of calcareous concretion soil depend largely on the shape, size and distribution of calcareous concretion soil besides the impact of soil layer. Due to the long time required for clay saturation, consolidation, and shearing, as well as the tedious sample preparation, larger triaxial tests of calcareous nodules have not been carried out. In this chapter, based on the medium triaxial test of calcareous nodules, the strength characteristics of remolded soil samples under different confining pressures are studied. By controlling parameters such as calcareous nodules particle size and water content, the impact of different test conditions on the strength of calcareous nodules is analysed, and the variation rule is analysed. It is concluded that the impact of nodular particle size on soil strength is not obvious at 20% nodular content. The impact of different water content on the strength of soil is more regular, showing hardening characteristics, in line with the natural law.


Author(s):  
Mathieu Audren ◽  
Simon Guihéneuf ◽  
Damien Rangeard ◽  
Arnaud Perrot

Development of earthen building materials is one of the answers that the construction sector can provide to tackle the accelerated climate change issue. However, these materials present a wide variability, even at the local scale, and their water durability can be difficult to ensure. In order to improve their durability regarding water and avoid its prejudicial effect on earthen material’s properties, the stabilisation with bio-polymers is an increasingly studied solution. In this paper a ten-minute erosion drip test is developed and performed for various combinations of Breton earths and bio-based additions or surface treatments (linseed oil, xanthan gum, casein, alginate, vegetal varnish and tannins). The final pitting depths and eroded volumes are compared and the evolution of erosion during the test is monitored. These results are also linked to previously obtained water capillary absorption coefficients. The obtained results enable to highlight the impact of bio-based additions on erodibility of earthen materials: linseed oil and xanthan gum help to protect the earth-based samples from erosion. Other original parameters characterizing the erosion of the samples during the drip test are suggested. Limitations of this type of erosion tests are also brought out.


2011 ◽  
Vol 343-344 ◽  
pp. 283-288
Author(s):  
Chih Ta Tsai ◽  
Chien Chih Chang ◽  
Lung Sheng Li ◽  
Tung Chin Kung

This paper shows that a new approach (i.e. cold-bonding technique) to recycle uncontaminated and innocuous lime sludge as coarse aggregates. The cold-bonding technique incorporates the principles of the cement chemistry and composite material to develop recycling coarse aggregates. Herein lime sludge was regarded as the main materials to produce recycling coarse aggregates, which meet the specifications of green building materials in Taiwan, using the cold-bonding technique instead of sintering method in light of the issues of reduction of waste, energy, and CO2 footprint. The results show that the specific gravity (in the oven-dry state, OD) of recycling coarse aggregate is in the range of 1.20 to 1.23; the absorption capacity is in 40.0 to 44.6 %; the dry loose density (i.e. unit weight) is 811 to 837 kg/m3; the single particle compressive strength at 28-day is in the range of 17.8 to 20.4 MPa; the particle cylindrical crushing strength ranges from 27.9 to 33.8 MPa; other characteristics also satisfies ASTM C33. The developed recycling coarse aggregates could increase the reuse and recycling of lime sludge, reduce the energy consumption and CO2 footprint, and diminish the impact on the environment and future generations.


2021 ◽  
Vol 352 ◽  
pp. 00001
Author(s):  
Stanislava Gašpercová ◽  
Linda Makovická Osvaldová ◽  
Erik Richnavský

The future of the whole world focuses on reducing waste produced by people. As the construction sector is one of the biggest producers of waste, a great deal of effort has been made to introduce this trend in modern construction. The “green” building sector, therefore, draws attention to natural and recyclable building materials. These include natural thermal insulation such as cork, fiberboard, hemp insulation, and even sheep wool insulation. Almost all types of such insulation are made from waste materials which, were they not reused in the form of thermal insulation, would end up as municipal or biodegradable waste. At the same time, we should point out that almost all “green” construction materials are flammable. This feature is not very advantageous from the point of view of fire protection and it can significantly affect the fire safety of a construction. It is for this reason that the main objective of this research was to determine the impact of a radiant heat source on various types of thermal insulation used as plasterboard filling and to evaluate the possibilities of their use in sandwich constructions for fire protection purposes.


2021 ◽  
Vol 13 (16) ◽  
pp. 9016
Author(s):  
Yahong Dong ◽  
Md. Uzzal Hossain ◽  
Hongyang Li ◽  
Peng Liu

The inconsistency caused by different life cycle impact assessment (LCIA) methods is a long-term challenge for the life cycle assessment (LCA) community. It is necessary to systematically analyze the differences caused by LCIA methods and facilitate the fair comparison of LCA results. This study proposes an effective method of conversion factors (CFs) for converting the results of 8 LCIA methods for 14 impact categories and then demonstrates its application in the construction sector. Correlation analyses of the datasets of construction materials are conducted to develop CFs for the impact categories. A set of conversion cards are devised to present the CFs and the associated correlation information for the LCIA methods. It is revealed that the differences between LCIA methods are largely caused by the characterization methods, rather than due to the metrics. A comparison based only on the same metrics but ignoring the underlying LCIA mechanisms is misleading. High correlations are observed for the impact categories of climate change, acidification, eutrophication, and resource depletion. The developed CFs and conversion cards can greatly help LCA practitioners in the fair comparison of LCA results from different LCIA methods. Case studies are conducted, and verify that by applying the CFs the seemingly incomparable results from different LCIA methods become comparable. The CF method addresses the inconsistency problem of LCIA methods in a practical manner and helps improve the comparability and reliability of LCA studies in the construction sector. Suggestions are provided for the further development of LCIA conversion factors.


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